1. Field of the Invention
This invention relates to an apparatus for expanding and flaring the end of tubular material. In particular this invention is useful for the expanding and flaring the end of a malleable thin walled tube to form a female end so that another tube having a male end can be guided by the flare into engagement with the expanded female end to form a rigid sealable joint.
2. Description of the Prior Act
Tools have been used in the past to expand the ends of tubes to form the female portion of a joint. However, where the end of the tube is alone expanded without also providing a flare, proper alignment of the tubes to be joined can be difficult. Examples of potentially difficult alignment problems include "in the field" conditions where alignment is accomplished by hand, in factory conditions where joints are made automatically by machinery which is not capable of detecting slight degrees of misalignment, or in situations where extremely close tolerances are maintained between the inside diameter of the expanded tube and the outside diameter of the joining tube.
Flaring tube tools have been divised which may require a separate operation to accomplish the flaring after the expanding of the tube end has been accomplished. Other tools beneficially expand and flare a tube end in one continuous operation. Such tools expand the tube using forming rollers. Typically the rollers have a substantially constant diameter cylindrical surface or have a nose which tapers to the single constant cylindrical surface. The flare is made with a chamfer surface on a collar which follows the rollers and contacts the end of the tube after the rollers are rotated into the tube end. The collar also holds the expanding rollers in place. The chamfer begins at a diameter equal to or smaller than the expanded end of the tube and expands outwardly to a diameter greater than the naximum diameter of the lip of the tube which is ultimately flared. This device has several drawbacks including wasted power and possibly resultant damage to the end of the tube being flared. As the entire surface of the flared portion of the tube is in contact with the champfered collar, excessive frictional energy loss results. Also high pressure must be exerted on the tool as it is pushed into the tube in order to cause the flaring to occur to a suitable degree. The excessive friction causes heat buildup, scoring and potentially even tearing of the lip of the tube as it is being expanded.
The present invention solves the problems of simultaneously expanding and flaring the end of tubular material as will become more apparent from the summary of the invention, the description and the drawings which follow.
Thus, it is an object of the present invention to provide an apparatus for expanding and flaring the end of the tube simultaneously while reducing the frictional power loss, the heat buildup, excessive tool pressure, and the tube end scoring and tearing problems and associated problems in the tube expanding and flaring art.
These and other objects and advantages will be more fully understood with reference to the drawings and descriptions of the preferred embodiments which follow.